The man who stood just feet away from President Obama as he paid tribute to Nelson Mandela told ABC News today that he was having schizophrenic hallucinations during Tuesday's memorial service in front of a crowd of tens of thousands and millions more on television.

Thamsanqa Jantjie, who has been accused of pretending to be a sign language interpreter during the event, today described the moment he knew something was wrong during the memorial at FNB Stadium in Soweto, South Africa.

"It's when I see angels come into the stadium," he told ABC News in an interview at his home.

Jantjie said he felt compelled to keep signing because of the magnitude of the event.

"If I start panicking, I'll start being a problem," he also told The Associated Press.

Sign language interpreters, however, have said his signs were not real words. Jantjie would not comment on those accusations but insisted he'd done a good job.

Jantjie also admitted that he'd had many episodes over the years that have turned violent.

"But now it's under control because I'm under medication," he said, adding that he was on his medication the day of the memorial.

A routine six-month checkup was due to take place the day of the ceremony but had to be postponed, he said.

Jantjie was given accreditation by the memorial service's organizers but he was not screened by the U.S. Secret Service. In fact, he said that he was hired the day before the event, which was attended by more than 100 current and former heads of state.

The South African government told ABC News that it did not actually know what qualifications Jantjie had as an interpreter and admitted that it had been a mistake to hire him.

His employers have "vanished," according to Bogopane-Zulu, deputy minister of Women, Children and People with Disabilities.

Bogopane-Zulu apologized for Jantjie's actions today and said an investigation was underway, according to the AP.

In a statement to ABC News today, the Secret Service blamed the organizers and downplayed the threat to the president's safety, arguing that agents were always close to Obama.

"Program items such as stage participants or sign language interpreters were the responsibility of the host organizing committee. For the purposes of this memorial service, this would include vetting them for criminal history and other appropriate records checks," the agency said in a statement.